As Fast As Possible
Response time overdrive allows you to push the monitor’s response time speed (pixel transition time) in order to reduce trailing/ghosting of fast-moving objects. Depending on the refresh rate, too strong overdrive can cause pixel overshoot or inverse ghosting. You will find your monitor’s overdrive settings in its OSD (On-Screen Display) menu, usually under one of the following names: Overdrive, Response Time, TraceFree, or something similar.
In order to explain what response time overdrive is on a monitor, we’ll cover what the response time speed is first.
You can visit our ‘What Does Monitor Response Time Mean?’ article for a more detailed explanation but in short, a monitor’s response time speed indicates how fast a pixel can change from one color to another.
For instance, a 60Hz monitor refreshes the image 60 times per second, so there are 16.67 milliseconds between two refresh cycles.
If a monitor’s response time is slower than that – meaning that a pixel takes longer than 16.67ms to change, it will continue changing in the next frame, and that’s how you get visible trailing behind moving objects on the screen.
For a 144Hz monitor, the refresh cycle is 6.94ms, so the response time needs to be faster than that, and so on.
This is where the response time overdrive, also referred to as RTC (Response Time Compensation), comes into play to push the pixels to transition from one color to another more quickly.
Which Response Time Overdrive Option To Use?
To access the monitor’s overdrive settings, open the OSD (On-Screen Display) menu and look for the overdrive option, it’s usually under one of the following names: TraceFree (some ASUS monitors), Rampage Response, Overdrive, OD, or simply Response Time.
There should be at least a few options to choose from. Depending on the model, the overdrive levels will be named differently and some monitors may have more levels than the rest.
Generally, the levels are labeled as Slow, Normal, Fast, Faster – Low, Medium, High, Highest or simply by numbers. ASUS’ TraceFree option allows you to adjust the overdrive from 0 to 100 in increments of 10, for example. Some monitors will also have the option to turn the overdrive completely off.
Now, if you have a modern LED-backlight 60Hz/75Hz monitor, it’s highly unlikely that its response time is slower than the display’s refresh cycle.
In most cases, you won’t notice any prominent ghosting/trailing of fast-moving objects even with overdrive set to Off or Low, but the Medium/Normal setting will usually work best. Too much overdrive can introduce inverse ghosting or pixel overshoot, so don’t use it unless you experience excessive motion blur in fast-paced games.
With higher refresh rate displays, overdrive is necessary for the optimal gaming experience. To test what’s the best overdrive setting for your monitor’s refresh rate, we recommend using BlurBusters’ UFO ghosting test.
It’s important that a gaming monitor has a good overdrive implementation. Some monitors have poorly optimized overdrive, such as the Samsung CHG70, for example, which only has one overdrive preset that is too strong at lower frame rates resulting in prominent overshoot.
So, when looking for a gaming monitor, just looking at its response time specification may not be enough. In our monitor reviews, we always cover the display’s overdrive implementation if it’s noteworthy.
Response Time And Overdrive: IPS vs TN vs VA
Generally, monitor manufacturers just include the GtG (Gray to Gray) response time speed which is mostly 1ms for TN panels, and 3ms-5ms for IPS and VA panels. The LG 27GL850 is the first IPS display to achieve a GtG speed of 1ms.
The GtG specified response time speed indicates the fastest speed at which a pixel can change from one shade of gray to another under certain testing conditions with the highest overdrive option applied. So, always take these numbers with reservation.
For instance, a TN panel with a specified response time speed of 1ms (GtG) will usually have a normal response time of ~5ms. To get 1ms, you’ll need to apply overdrive. An average IPS panel will have a normal response time of ~9ms whereas VA panels usually have a response time of over 12ms.
Due to their quick response time, TN panel displays are favorite among competitive FPS gamers despite their inferior color quality and viewing angles. VA panels have the worst response time but they have the highest contrast ratio out of these three panel technologies.
Such high contrast ratio allows them to produce very deep black shades out of which pixels take longer to change from. Consequently, you get visible smearing and ghosting in fast-paced scenes, particularly where dark pixels are involved.
While the amount of ghosting on VA panels is too high for competitive gamers, it’s tolerable for casual gaming as in return you get an exceptional image quality at a reasonable price. IPS panels offer a good balance between the two technologies but are also more expensive.
MPRT vs GtG Response Time Speed
You will also notice that some monitor manufacturers include a 1ms MPRT (Moving Picture Response Time) specification as well. This is not the same as the GtG response time. Instead, MPRT indicates that the monitor has a Motion Blur Reduction technology which via backlight strobing reduces the perceived ghosting.
The problem occurs when a monitor manufacturer states the display’s MPRT speed of 1ms but doesn’t show its GtG response time thus misleading potential users that the monitor has a 1ms response time speed whereas it could actually have a 4ms-5ms GtG response time instead.
Motion Blur Reduction provides a CRT-like motion clarity but has its downsides as well: it decreases the monitor’s maximum brightness while active and it introduces screen flicker – it also cannot work at the same time as VRR (variable refresh rate) technologies such as FreeSync and G-SYNC on most monitors.
Overdrive And Variable Refresh Rate
When using FreeSync/G-SYNC which synchronizes the monitor’s refresh rate with the GPU’s frame rate in order to eliminate screen tearing and stuttering, there are a few additional things to keep in mind concerning overdrive.
Gaming monitors with an integrated G-SYNC module have variable overdrive which allows them to change the overdrive setting according to the refresh rate for the optimal performance at any frame/refresh rate.
FreeSync monitors, on the other hand, don’t have this ability. So, for example, if you’re running at 144FPS with High overdrive, and your FPS rate drops to ~60FPS, the overdrive will be too strong for 60Hz/FPS and therefore introduce overshoot. Luckily, this doesn’t happen often.
Some FreeSync models, such as the Nixeus EDG27 feature Adaptive Overdrive which automatically changes the overdrive preset according to the refresh rate. Although it’s not as effective as G-SYNC’s variable overdrive, it does prevent ghosting and overshoot in certain scenarios.
On the other hand, certain FreeSync monitors cannot even simultaneously run FreeSync and the strongest overdrive option.
In this case, we recommend disabling FreeSync and using High overdrive at higher frame rates or using Medium overdrive and FreeSync at lower frame rates. This will depend on your preference as well though, whether you’re more sensitive to screen tearing or to ghosting.
Rob is a software engineer with a Bachelor’s degree from the University of Denver. He now works full-time managing DisplayNinja while coding his own projects on the side.